Firstly, sorry, I know that there are many threads here on this topic, when I search I get a long list. As I look down this however, 2012, 2013... Quite old.
Could WPMU please provide some sort of statement on recurring bookings for this plugin? Everything else about the plugin is great. I'm currently deciding whether to do some coding on this myself, or look for another plugin to use for one of my sites, and 2 - 3 client jobs that I have in the pipeline, so I'd appreciate some info on whether WPMU are likely to be adding this feature any time in the near future...